Cryosurgery consists of deep-freezing tissue in situ to destroy, manipulate or change its structure. It is only recently that cryosurgery has gained popularity as a minimally invasive procedure, thanks to the advances in modern imaging systems. Its use in deep soft tissues and on superficial lesions has been extensively documented and its effectiveness well established. The remaining obstacle to its more widespread use resides in estimating the extent of the ice ball during procedures and estimating the extent of necrosis. Immediately following cryosurgery. This has resulted in a slow adoption of its use, particularly in the US. We propose to combine cryosurgery with impedance measurements to obtain an accurate assessment of the size and shape of the ice ball during cryosurgery. A custom cryoprobe will be designed which will allow impedance measurements to be made during a procedure. In addition, an existing impedance analyzer will be used under computer control to perform the measurements in real time and reconstruct the ice ball shape and size using the impedance recorded. Finally a series of experiments in tissue- mimicking phantoms will be conducted to evaluate the system's capability in gauging the size and shape of the ice ball. PROPOSED COMMERCIAL APPLICATIONS: The remaining obstacle to the more widespread use of cryosurgery resides in estimating the extent of the ice ball during deep procedures and estimating the extent of necrosis immediately following cryosurgery. This has resulted in a slow adoption of its user, particularly in the US. We proposed to combine cryosurgery with Electrical Impedance Tomography (EIT) to obtain an accurate assessment of the size and shape of the ice ball during cryosurgical procedures. Hanover Medical Imaging Project LLC hopes to develop an effective method to accurately monitor the size of cryolesions. This collaboration between Hanover Medical Imaging Project LLC and CryoFlex, Inc., a firm that manufactures and distributes cryosurgery equipment may result in a very significant competitive advantage in the marketing of their devices. The integration of EIT capabilities with their existing equipment would constitutive a unique and possible very significant improvement in the current state of the art in cryosurgery.